When using an IEEE 802.11 wireless LAN, users must set wireless parameters such as a network identifier (ESSID), a frequency channel, an encryption scheme, an encryption key, an authentication scheme, an authentication key, and the like. Because these settings operations are complicated, methods have been proposed for automatically setting wireless parameters between terminals. For example, a method for transferring wireless parameter settings between a relay station (access point) and a terminal station (station) from the access point to the station with a simple operation has been implemented as an actual product.
In recent years, an organization called the Wi-Fi Alliance has developed a standard for automatic setting of wireless parameters called Wi-Fi Protected Setup (WPS), which has already been implemented in some products.
According to WPS, wireless parameters are provided from a Registrar to an Enrollee using a Registration protocol, a special protocol for setting wireless parameters. The Registrar is an apparatus that manages wireless parameters and provides wireless parameters to Enrollees. The Enrollee is an apparatus that receives wireless parameters from a Registrar.
The communication between the Registrar and the Enrollee according to the Registration protocol is performed using EAP (Extensible Authentication Protocol) packets. The EAP packets are packets that enable communication between the Registrar and the Enrollee without an encryption or authentication.
An example will be described in which wireless parameters are provided from an access point that acts as a Registrar to a station that acts as an Enrollee. First, the station searches for a network to which the access point belongs, and temporarily joins the network. At this point in time, the ESSIDs and frequency channels of the access point and the station are the same, but the encryption key, authentication key and the like are not the same, and thus, ordinary data communication using an encryption or authentication is not possible.
The access point and the station perform transmission/reception of messages using EAP packets according to the Registration protocol, and thereby, wireless parameters are provided from the access point to the station. The provided wireless parameters are newly set in the station, and thereby, data communication using an encryption or authentication is established between the station and the access point.
Currently, public wireless LANs are available which provide Internet connection services by installing access points in public places such as fast-food restaurants, railway stations, airports, and the like. Such a public wireless LAN authenticates users (performs user authentication) using authentication information, such as user IDs and passwords, in order to check whether or not they have an authorized account, and permits only users who have an authorized account to access the Internet. However, this user authentication has to be executed each time a user uses the public wireless LAN, which is troublesome for the user. To address this, for example, Japanese Patent Laid-Open No. 2004-80138 proposes a method for automating user authentication, wireless connection to a public wireless LAN, and the like.
According to the WPS, a PIN code is set in the Registrar and the Enrollee, and if it is confirmed that the PIN code set in the Registrar and the Enrollee are the same in the Registration protocol, wireless parameters are exchanged. So, this system does not permit the exchange of wireless parameters with unintended devices.
Nevertheless, a case can be conceived in which the WPS is applied to a public wireless LAN. However, since general users cannot operate access points, it is impossible to set a PIN code in the Registrars, so the application of the WPS to a public wireless LAN is not possible.
Likewise, when a configuration is adopted in which general users can set a PIN code in access points, even users who do not have an authorized account can easily set a PIN code and obtain the wireless LAN parameters, causing problems in terms of security.
In addition, in public wireless LANs, after the wireless parameters have been set, user authentication has to be performed manually or with dedicated software, requiring users to perform troublesome operations.